Subject: linux-next: manual merge of the bcon tree

From: Thierry Reding <[email-masked]>
Date: Mon, 30 Sep 2013 13:26:03 +0200

Today's linux-next merge of the bcon tree got conflicts in

	drivers/block/Kconfig
	kernel/printk.c

I fixed it up (see below). Please check if the resolution looks correct.

Thanks,
Thierry
---
diff --cc drivers/block/Kconfig
index 555aed0,06eb42f..4cd9323
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@@ -541,14 -544,10 +541,20 @@@ config BLK_DEV_RB
  
  	  If unsure, say N.
  
 +config BLK_DEV_RSXX
 +	tristate "IBM Flash Adapter 900GB Full Height PCIe Device Driver"
 +	depends on PCI
 +	help
 +	  Device driver for IBM's high speed PCIe SSD
 +	  storage device: Flash Adapter 900GB Full Height.
 +
 +	  To compile this driver as a module, choose M here: the
 +	  module will be called rsxx.
 +
+ config BLOCKCONSOLE
+ 	bool "Block device console logging support"
+ 	help
+ 	  This enables logging to block devices.
+ 	  See <file:Documentation/block/blockconsole.txt> for details.
+ 
  endif # BLK_DEV
diff --cc drivers/block/Makefile
index f33b366,99c5c2e..08da80f
--- a/drivers/block/Makefile
+++ b/drivers/block/Makefile
@@@ -40,9 -40,6 +40,10 @@@ obj-$(CONFIG_XEN_BLKDEV_BACKEND)	+= xen
  obj-$(CONFIG_BLK_DEV_DRBD)     += drbd/
  obj-$(CONFIG_BLK_DEV_RBD)     += rbd.o
  obj-$(CONFIG_BLK_DEV_PCIESSD_MTIP32XX)	+= mtip32xx/
+ obj-$(CONFIG_BLOCKCONSOLE)	+= blockconsole.o
  
 +obj-$(CONFIG_BLK_DEV_RSXX) += rsxx/
 +
 +nvme-y		:= nvme-core.o nvme-scsi.o
 +skd-y		:= skd_main.o
  swim_mod-y	:= swim.o swim_asm.o
diff --cc kernel/printk/printk.c
index b4e8500,0000000..1cba1ea
mode 100644,000000..100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@@ -1,2910 -1,0 +1,2911 @@@
 +/*
 + *  linux/kernel/printk.c
 + *
 + *  Copyright (C) 1991, 1992  Linus Torvalds
 + *
 + * Modified to make sys_syslog() more flexible: added commands to
 + * return the last 4k of kernel messages, regardless of whether
 + * they've been read or not.  Added option to suppress kernel printk's
 + * to the console.  Added hook for sending the console messages
 + * elsewhere, in preparation for a serial line console (someday).
 + * Ted Ts'o, 2/11/93.
 + * Modified for sysctl support, 1/8/97, Chris Horn.
 + * Fixed SMP synchronization, 08/08/99, Manfred Spraul
 + *     [email-masked]
 + * Rewrote bits to get rid of console_lock
 + *	01Mar01 Andrew Morton
 + */
 +
 +#include <linux/kernel.h>
 +#include <linux/mm.h>
 +#include <linux/tty.h>
 +#include <linux/tty_driver.h>
 +#include <linux/console.h>
 +#include <linux/init.h>
 +#include <linux/jiffies.h>
 +#include <linux/nmi.h>
 +#include <linux/module.h>
 +#include <linux/moduleparam.h>
 +#include <linux/interrupt.h>			/* For in_interrupt() */
 +#include <linux/delay.h>
 +#include <linux/smp.h>
 +#include <linux/security.h>
 +#include <linux/bootmem.h>
 +#include <linux/memblock.h>
 +#include <linux/aio.h>
 +#include <linux/syscalls.h>
 +#include <linux/kexec.h>
 +#include <linux/kdb.h>
 +#include <linux/ratelimit.h>
 +#include <linux/kmsg_dump.h>
 +#include <linux/syslog.h>
 +#include <linux/cpu.h>
 +#include <linux/notifier.h>
 +#include <linux/rculist.h>
 +#include <linux/poll.h>
 +#include <linux/irq_work.h>
 +#include <linux/utsname.h>
 +
 +#include <asm/uaccess.h>
 +
 +#define CREATE_TRACE_POINTS
 +#include <trace/events/printk.h>
 +
 +#include "console_cmdline.h"
 +#include "braille.h"
 +
 +/* printk's without a loglevel use this.. */
 +#define DEFAULT_MESSAGE_LOGLEVEL CONFIG_DEFAULT_MESSAGE_LOGLEVEL
 +
 +/* We show everything that is MORE important than this.. */
 +#define MINIMUM_CONSOLE_LOGLEVEL 1 /* Minimum loglevel we let people use */
 +#define DEFAULT_CONSOLE_LOGLEVEL 7 /* anything MORE serious than KERN_DEBUG */
 +
 +int console_printk[4] = {
 +	DEFAULT_CONSOLE_LOGLEVEL,	/* console_loglevel */
 +	DEFAULT_MESSAGE_LOGLEVEL,	/* default_message_loglevel */
 +	MINIMUM_CONSOLE_LOGLEVEL,	/* minimum_console_loglevel */
 +	DEFAULT_CONSOLE_LOGLEVEL,	/* default_console_loglevel */
 +};
 +
 +/*
 + * Low level drivers may need that to know if they can schedule in
 + * their unblank() callback or not. So let's export it.
 + */
 +int oops_in_progress;
 +EXPORT_SYMBOL(oops_in_progress);
 +
 +/*
 + * console_sem protects the console_drivers list, and also
 + * provides serialisation for access to the entire console
 + * driver system.
 + */
 +static DEFINE_SEMAPHORE(console_sem);
 +struct console *console_drivers;
 +EXPORT_SYMBOL_GPL(console_drivers);
 +
 +#ifdef CONFIG_LOCKDEP
 +static struct lockdep_map console_lock_dep_map = {
 +	.name = "console_lock"
 +};
 +#endif
 +
 +/*
 + * This is used for debugging the mess that is the VT code by
 + * keeping track if we have the console semaphore held. It's
 + * definitely not the perfect debug tool (we don't know if _WE_
 + * hold it are racing, but it helps tracking those weird code
 + * path in the console code where we end up in places I want
 + * locked without the console sempahore held
 + */
 +static int console_locked, console_suspended;
 +
 +/*
 + * If exclusive_console is non-NULL then only this console is to be printed to.
 + */
 +static struct console *exclusive_console;
 +
 +/*
 + *	Array of consoles built from command line options (console=)
 + */
 +
 +#define MAX_CMDLINECONSOLES 8
 +
 +static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES];
 +
 +static int selected_console = -1;
 +static int preferred_console = -1;
 +int console_set_on_cmdline;
 +EXPORT_SYMBOL(console_set_on_cmdline);
 +
 +/* Flag: console code may call schedule() */
 +static int console_may_schedule;
 +
 +/*
 + * The printk log buffer consists of a chain of concatenated variable
 + * length records. Every record starts with a record header, containing
 + * the overall length of the record.
 + *
 + * The heads to the first and last entry in the buffer, as well as the
 + * sequence numbers of these both entries are maintained when messages
 + * are stored..
 + *
 + * If the heads indicate available messages, the length in the header
 + * tells the start next message. A length == 0 for the next message
 + * indicates a wrap-around to the beginning of the buffer.
 + *
 + * Every record carries the monotonic timestamp in microseconds, as well as
 + * the standard userspace syslog level and syslog facility. The usual
 + * kernel messages use LOG_KERN; userspace-injected messages always carry
 + * a matching syslog facility, by default LOG_USER. The origin of every
 + * message can be reliably determined that way.
 + *
 + * The human readable log message directly follows the message header. The
 + * length of the message text is stored in the header, the stored message
 + * is not terminated.
 + *
 + * Optionally, a message can carry a dictionary of properties (key/value pairs),
 + * to provide userspace with a machine-readable message context.
 + *
 + * Examples for well-defined, commonly used property names are:
 + *   DEVICE=b12:8               device identifier
 + *                                b12:8         block dev_t
 + *                                c127:3        char dev_t
 + *                                n8            netdev ifindex
 + *                                +sound:card0  subsystem:devname
 + *   SUBSYSTEM=pci              driver-core subsystem name
 + *
 + * Valid characters in property names are [a-zA-Z0-9.-_]. The plain text value
 + * follows directly after a '=' character. Every property is terminated by
 + * a '\0' character. The last property is not terminated.
 + *
 + * Example of a message structure:
 + *   0000  ff 8f 00 00 00 00 00 00      monotonic time in nsec
 + *   0008  34 00                        record is 52 bytes long
 + *   000a        0b 00                  text is 11 bytes long
 + *   000c              1f 00            dictionary is 23 bytes long
 + *   000e                    03 00      LOG_KERN (facility) LOG_ERR (level)
 + *   0010  69 74 27 73 20 61 20 6c      "it's a l"
 + *         69 6e 65                     "ine"
 + *   001b           44 45 56 49 43      "DEVIC"
 + *         45 3d 62 38 3a 32 00 44      "E=b8:2\0D"
 + *         52 49 56 45 52 3d 62 75      "RIVER=bu"
 + *         67                           "g"
 + *   0032     00 00 00                  padding to next message header
 + *
 + * The 'struct printk_log' buffer header must never be directly exported to
 + * userspace, it is a kernel-private implementation detail that might
 + * need to be changed in the future, when the requirements change.
 + *
 + * /dev/kmsg exports the structured data in the following line format:
 + *   "level,sequnum,timestamp;<message text>\n"
 + *
 + * The optional key/value pairs are attached as continuation lines starting
 + * with a space character and terminated by a newline. All possible
 + * non-prinatable characters are escaped in the "\xff" notation.
 + *
 + * Users of the export format should ignore possible additional values
 + * separated by ',', and find the message after the ';' character.
 + */
 +
 +enum log_flags {
 +	LOG_NOCONS	= 1,	/* already flushed, do not print to console */
 +	LOG_NEWLINE	= 2,	/* text ended with a newline */
 +	LOG_PREFIX	= 4,	/* text started with a prefix */
 +	LOG_CONT	= 8,	/* text is a fragment of a continuation line */
 +};
 +
 +struct printk_log {
 +	u64 ts_nsec;		/* timestamp in nanoseconds */
 +	u16 len;		/* length of entire record */
 +	u16 text_len;		/* length of text buffer */
 +	u16 dict_len;		/* length of dictionary buffer */
 +	u8 facility;		/* syslog facility */
 +	u8 flags:5;		/* internal record flags */
 +	u8 level:3;		/* syslog level */
 +};
 +
 +/*
 + * The logbuf_lock protects kmsg buffer, indices, counters. It is also
 + * used in interesting ways to provide interlocking in console_unlock();
 + */
 +static DEFINE_RAW_SPINLOCK(logbuf_lock);
 +
 +#ifdef CONFIG_PRINTK
 +DECLARE_WAIT_QUEUE_HEAD(log_wait);
 +/* the next printk record to read by syslog(READ) or /proc/kmsg */
 +static u64 syslog_seq;
 +static u32 syslog_idx;
 +static enum log_flags syslog_prev;
 +static size_t syslog_partial;
 +
 +/* index and sequence number of the first record stored in the buffer */
 +static u64 log_first_seq;
 +static u32 log_first_idx;
 +
 +/* index and sequence number of the next record to store in the buffer */
 +static u64 log_next_seq;
 +static u32 log_next_idx;
 +
 +/* the next printk record to write to the console */
 +static u64 console_seq;
 +static u32 console_idx;
 +static enum log_flags console_prev;
 +
 +/* the next printk record to read after the last 'clear' command */
 +static u64 clear_seq;
 +static u32 clear_idx;
 +
 +#define PREFIX_MAX		32
 +#define LOG_LINE_MAX		1024 - PREFIX_MAX
 +
 +/* record buffer */
 +#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
 +#define LOG_ALIGN 4
 +#else
 +#define LOG_ALIGN __alignof__(struct printk_log)
 +#endif
 +#define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT)
 +static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN);
 +static char *log_buf = __log_buf;
 +static u32 log_buf_len = __LOG_BUF_LEN;
 +
 +/* cpu currently holding logbuf_lock */
 +static volatile unsigned int logbuf_cpu = UINT_MAX;
 +
 +/* human readable text of the record */
 +static char *log_text(const struct printk_log *msg)
 +{
 +	return (char *)msg + sizeof(struct printk_log);
 +}
 +
 +/* optional key/value pair dictionary attached to the record */
 +static char *log_dict(const struct printk_log *msg)
 +{
 +	return (char *)msg + sizeof(struct printk_log) + msg->text_len;
 +}
 +
 +/* get record by index; idx must point to valid msg */
 +static struct printk_log *log_from_idx(u32 idx)
 +{
 +	struct printk_log *msg = (struct printk_log *)(log_buf + idx);
 +
 +	/*
 +	 * A length == 0 record is the end of buffer marker. Wrap around and
 +	 * read the message at the start of the buffer.
 +	 */
 +	if (!msg->len)
 +		return (struct printk_log *)log_buf;
 +	return msg;
 +}
 +
 +/* get next record; idx must point to valid msg */
 +static u32 log_next(u32 idx)
 +{
 +	struct printk_log *msg = (struct printk_log *)(log_buf + idx);
 +
 +	/* length == 0 indicates the end of the buffer; wrap */
 +	/*
 +	 * A length == 0 record is the end of buffer marker. Wrap around and
 +	 * read the message at the start of the buffer as *this* one, and
 +	 * return the one after that.
 +	 */
 +	if (!msg->len) {
 +		msg = (struct printk_log *)log_buf;
 +		return msg->len;
 +	}
 +	return idx + msg->len;
 +}
 +
 +/* insert record into the buffer, discard old ones, update heads */
 +static void log_store(int facility, int level,
 +		      enum log_flags flags, u64 ts_nsec,
 +		      const char *dict, u16 dict_len,
 +		      const char *text, u16 text_len)
 +{
 +	struct printk_log *msg;
 +	u32 size, pad_len;
 +
 +	/* number of '\0' padding bytes to next message */
 +	size = sizeof(struct printk_log) + text_len + dict_len;
 +	pad_len = (-size) & (LOG_ALIGN - 1);
 +	size += pad_len;
 +
 +	while (log_first_seq < log_next_seq) {
 +		u32 free;
 +
 +		if (log_next_idx > log_first_idx)
 +			free = max(log_buf_len - log_next_idx, log_first_idx);
 +		else
 +			free = log_first_idx - log_next_idx;
 +
 +		if (free > size + sizeof(struct printk_log))
 +			break;
 +
 +		/* drop old messages until we have enough contiuous space */
 +		log_first_idx = log_next(log_first_idx);
 +		log_first_seq++;
 +	}
 +
 +	if (log_next_idx + size + sizeof(struct printk_log) >= log_buf_len) {
 +		/*
 +		 * This message + an additional empty header does not fit
 +		 * at the end of the buffer. Add an empty header with len == 0
 +		 * to signify a wrap around.
 +		 */
 +		memset(log_buf + log_next_idx, 0, sizeof(struct printk_log));
 +		log_next_idx = 0;
 +	}
 +
 +	/* fill message */
 +	msg = (struct printk_log *)(log_buf + log_next_idx);
 +	memcpy(log_text(msg), text, text_len);
 +	msg->text_len = text_len;
 +	memcpy(log_dict(msg), dict, dict_len);
 +	msg->dict_len = dict_len;
 +	msg->facility = facility;
 +	msg->level = level & 7;
 +	msg->flags = flags & 0x1f;
 +	if (ts_nsec > 0)
 +		msg->ts_nsec = ts_nsec;
 +	else
 +		msg->ts_nsec = local_clock();
 +	memset(log_dict(msg) + dict_len, 0, pad_len);
 +	msg->len = sizeof(struct printk_log) + text_len + dict_len + pad_len;
 +
 +	/* insert message */
 +	log_next_idx += msg->len;
 +	log_next_seq++;
 +}
 +
 +#ifdef CONFIG_SECURITY_DMESG_RESTRICT
 +int dmesg_restrict = 1;
 +#else
 +int dmesg_restrict;
 +#endif
 +
 +static int syslog_action_restricted(int type)
 +{
 +	if (dmesg_restrict)
 +		return 1;
 +	/*
 +	 * Unless restricted, we allow "read all" and "get buffer size"
 +	 * for everybody.
 +	 */
 +	return type != SYSLOG_ACTION_READ_ALL &&
 +	       type != SYSLOG_ACTION_SIZE_BUFFER;
 +}
 +
 +static int check_syslog_permissions(int type, bool from_file)
 +{
 +	/*
 +	 * If this is from /proc/kmsg and we've already opened it, then we've
 +	 * already done the capabilities checks at open time.
 +	 */
 +	if (from_file && type != SYSLOG_ACTION_OPEN)
 +		return 0;
 +
 +	if (syslog_action_restricted(type)) {
 +		if (capable(CAP_SYSLOG))
 +			return 0;
 +		/*
 +		 * For historical reasons, accept CAP_SYS_ADMIN too, with
 +		 * a warning.
 +		 */
 +		if (capable(CAP_SYS_ADMIN)) {
 +			pr_warn_once("%s (%d): Attempt to access syslog with "
 +				     "CAP_SYS_ADMIN but no CAP_SYSLOG "
 +				     "(deprecated).\n",
 +				 current->comm, task_pid_nr(current));
 +			return 0;
 +		}
 +		return -EPERM;
 +	}
 +	return security_syslog(type);
 +}
 +
 +
 +/* /dev/kmsg - userspace message inject/listen interface */
 +struct devkmsg_user {
 +	u64 seq;
 +	u32 idx;
 +	enum log_flags prev;
 +	struct mutex lock;
 +	char buf[8192];
 +};
 +
 +static ssize_t devkmsg_writev(struct kiocb *iocb, const struct iovec *iv,
 +			      unsigned long count, loff_t pos)
 +{
 +	char *buf, *line;
 +	int i;
 +	int level = default_message_loglevel;
 +	int facility = 1;	/* LOG_USER */
 +	size_t len = iov_length(iv, count);
 +	ssize_t ret = len;
 +
 +	if (len > LOG_LINE_MAX)
 +		return -EINVAL;
 +	buf = kmalloc(len+1, GFP_KERNEL);
 +	if (buf == NULL)
 +		return -ENOMEM;
 +
 +	line = buf;
 +	for (i = 0; i < count; i++) {
 +		if (copy_from_user(line, iv[i].iov_base, iv[i].iov_len)) {
 +			ret = -EFAULT;
 +			goto out;
 +		}
 +		line += iv[i].iov_len;
 +	}
 +
 +	/*
 +	 * Extract and skip the syslog prefix <[0-9]*>. Coming from userspace
 +	 * the decimal value represents 32bit, the lower 3 bit are the log
 +	 * level, the rest are the log facility.
 +	 *
 +	 * If no prefix or no userspace facility is specified, we
 +	 * enforce LOG_USER, to be able to reliably distinguish
 +	 * kernel-generated messages from userspace-injected ones.
 +	 */
 +	line = buf;
 +	if (line[0] == '<') {
 +		char *endp = NULL;
 +
 +		i = simple_strtoul(line+1, &endp, 10);
 +		if (endp && endp[0] == '>') {
 +			level = i & 7;
 +			if (i >> 3)
 +				facility = i >> 3;
 +			endp++;
 +			len -= endp - line;
 +			line = endp;
 +		}
 +	}
 +	line[len] = '\0';
 +
 +	printk_emit(facility, level, NULL, 0, "%s", line);
 +out:
 +	kfree(buf);
 +	return ret;
 +}
 +
 +static ssize_t devkmsg_read(struct file *file, char __user *buf,
 +			    size_t count, loff_t *ppos)
 +{
 +	struct devkmsg_user *user = file->private_data;
 +	struct printk_log *msg;
 +	u64 ts_usec;
 +	size_t i;
 +	char cont = '-';
 +	size_t len;
 +	ssize_t ret;
 +
 +	if (!user)
 +		return -EBADF;
 +
 +	ret = mutex_lock_interruptible(&user->lock);
 +	if (ret)
 +		return ret;
 +	raw_spin_lock_irq(&logbuf_lock);
 +	while (user->seq == log_next_seq) {
 +		if (file->f_flags & O_NONBLOCK) {
 +			ret = -EAGAIN;
 +			raw_spin_unlock_irq(&logbuf_lock);
 +			goto out;
 +		}
 +
 +		raw_spin_unlock_irq(&logbuf_lock);
 +		ret = wait_event_interruptible(log_wait,
 +					       user->seq != log_next_seq);
 +		if (ret)
 +			goto out;
 +		raw_spin_lock_irq(&logbuf_lock);
 +	}
 +
 +	if (user->seq < log_first_seq) {
 +		/* our last seen message is gone, return error and reset */
 +		user->idx = log_first_idx;
 +		user->seq = log_first_seq;
 +		ret = -EPIPE;
 +		raw_spin_unlock_irq(&logbuf_lock);
 +		goto out;
 +	}
 +
 +	msg = log_from_idx(user->idx);
 +	ts_usec = msg->ts_nsec;
 +	do_div(ts_usec, 1000);
 +
 +	/*
 +	 * If we couldn't merge continuation line fragments during the print,
 +	 * export the stored flags to allow an optional external merge of the
 +	 * records. Merging the records isn't always neccessarily correct, like
 +	 * when we hit a race during printing. In most cases though, it produces
 +	 * better readable output. 'c' in the record flags mark the first
 +	 * fragment of a line, '+' the following.
 +	 */
 +	if (msg->flags & LOG_CONT && !(user->prev & LOG_CONT))
 +		cont = 'c';
 +	else if ((msg->flags & LOG_CONT) ||
 +		 ((user->prev & LOG_CONT) && !(msg->flags & LOG_PREFIX)))
 +		cont = '+';
 +
 +	len = sprintf(user->buf, "%u,%llu,%llu,%c;",
 +		      (msg->facility << 3) | msg->level,
 +		      user->seq, ts_usec, cont);
 +	user->prev = msg->flags;
 +
 +	/* escape non-printable characters */
 +	for (i = 0; i < msg->text_len; i++) {
 +		unsigned char c = log_text(msg)[i];
 +
 +		if (c < ' ' || c >= 127 || c == '\\')
 +			len += sprintf(user->buf + len, "\\x%02x", c);
 +		else
 +			user->buf[len++] = c;
 +	}
 +	user->buf[len++] = '\n';
 +
 +	if (msg->dict_len) {
 +		bool line = true;
 +
 +		for (i = 0; i < msg->dict_len; i++) {
 +			unsigned char c = log_dict(msg)[i];
 +
 +			if (line) {
 +				user->buf[len++] = ' ';
 +				line = false;
 +			}
 +
 +			if (c == '\0') {
 +				user->buf[len++] = '\n';
 +				line = true;
 +				continue;
 +			}
 +
 +			if (c < ' ' || c >= 127 || c == '\\') {
 +				len += sprintf(user->buf + len, "\\x%02x", c);
 +				continue;
 +			}
 +
 +			user->buf[len++] = c;
 +		}
 +		user->buf[len++] = '\n';
 +	}
 +
 +	user->idx = log_next(user->idx);
 +	user->seq++;
 +	raw_spin_unlock_irq(&logbuf_lock);
 +
 +	if (len > count) {
 +		ret = -EINVAL;
 +		goto out;
 +	}
 +
 +	if (copy_to_user(buf, user->buf, len)) {
 +		ret = -EFAULT;
 +		goto out;
 +	}
 +	ret = len;
 +out:
 +	mutex_unlock(&user->lock);
 +	return ret;
 +}
 +
 +static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
 +{
 +	struct devkmsg_user *user = file->private_data;
 +	loff_t ret = 0;
 +
 +	if (!user)
 +		return -EBADF;
 +	if (offset)
 +		return -ESPIPE;
 +
 +	raw_spin_lock_irq(&logbuf_lock);
 +	switch (whence) {
 +	case SEEK_SET:
 +		/* the first record */
 +		user->idx = log_first_idx;
 +		user->seq = log_first_seq;
 +		break;
 +	case SEEK_DATA:
 +		/*
 +		 * The first record after the last SYSLOG_ACTION_CLEAR,
 +		 * like issued by 'dmesg -c'. Reading /dev/kmsg itself
 +		 * changes no global state, and does not clear anything.
 +		 */
 +		user->idx = clear_idx;
 +		user->seq = clear_seq;
 +		break;
 +	case SEEK_END:
 +		/* after the last record */
 +		user->idx = log_next_idx;
 +		user->seq = log_next_seq;
 +		break;
 +	default:
 +		ret = -EINVAL;
 +	}
 +	raw_spin_unlock_irq(&logbuf_lock);
 +	return ret;
 +}
 +
 +static unsigned int devkmsg_poll(struct file *file, poll_table *wait)
 +{
 +	struct devkmsg_user *user = file->private_data;
 +	int ret = 0;
 +
 +	if (!user)
 +		return POLLERR|POLLNVAL;
 +
 +	poll_wait(file, &log_wait, wait);
 +
 +	raw_spin_lock_irq(&logbuf_lock);
 +	if (user->seq < log_next_seq) {
 +		/* return error when data has vanished underneath us */
 +		if (user->seq < log_first_seq)
 +			ret = POLLIN|POLLRDNORM|POLLERR|POLLPRI;
 +		else
 +			ret = POLLIN|POLLRDNORM;
 +	}
 +	raw_spin_unlock_irq(&logbuf_lock);
 +
 +	return ret;
 +}
 +
 +static int devkmsg_open(struct inode *inode, struct file *file)
 +{
 +	struct devkmsg_user *user;
 +	int err;
 +
 +	/* write-only does not need any file context */
 +	if ((file->f_flags & O_ACCMODE) == O_WRONLY)
 +		return 0;
 +
 +	err = check_syslog_permissions(SYSLOG_ACTION_READ_ALL,
 +				       SYSLOG_FROM_READER);
 +	if (err)
 +		return err;
 +
 +	user = kmalloc(sizeof(struct devkmsg_user), GFP_KERNEL);
 +	if (!user)
 +		return -ENOMEM;
 +
 +	mutex_init(&user->lock);
 +
 +	raw_spin_lock_irq(&logbuf_lock);
 +	user->idx = log_first_idx;
 +	user->seq = log_first_seq;
 +	raw_spin_unlock_irq(&logbuf_lock);
 +
 +	file->private_data = user;
 +	return 0;
 +}
 +
 +static int devkmsg_release(struct inode *inode, struct file *file)
 +{
 +	struct devkmsg_user *user = file->private_data;
 +
 +	if (!user)
 +		return 0;
 +
 +	mutex_destroy(&user->lock);
 +	kfree(user);
 +	return 0;
 +}
 +
 +const struct file_operations kmsg_fops = {
 +	.open = devkmsg_open,
 +	.read = devkmsg_read,
 +	.aio_write = devkmsg_writev,
 +	.llseek = devkmsg_llseek,
 +	.poll = devkmsg_poll,
 +	.release = devkmsg_release,
 +};
 +
 +#ifdef CONFIG_KEXEC
 +/*
 + * This appends the listed symbols to /proc/vmcoreinfo
 + *
 + * /proc/vmcoreinfo is used by various utiilties, like crash and makedumpfile to
 + * obtain access to symbols that are otherwise very difficult to locate.  These
 + * symbols are specifically used so that utilities can access and extract the
 + * dmesg log from a vmcore file after a crash.
 + */
 +void log_buf_kexec_setup(void)
 +{
 +	VMCOREINFO_SYMBOL(log_buf);
 +	VMCOREINFO_SYMBOL(log_buf_len);
 +	VMCOREINFO_SYMBOL(log_first_idx);
 +	VMCOREINFO_SYMBOL(log_next_idx);
 +	/*
 +	 * Export struct printk_log size and field offsets. User space tools can
 +	 * parse it and detect any changes to structure down the line.
 +	 */
 +	VMCOREINFO_STRUCT_SIZE(printk_log);
 +	VMCOREINFO_OFFSET(printk_log, ts_nsec);
 +	VMCOREINFO_OFFSET(printk_log, len);
 +	VMCOREINFO_OFFSET(printk_log, text_len);
 +	VMCOREINFO_OFFSET(printk_log, dict_len);
 +}
 +#endif
 +
 +/* requested log_buf_len from kernel cmdline */
 +static unsigned long __initdata new_log_buf_len;
 +
 +/* save requested log_buf_len since it's too early to process it */
 +static int __init log_buf_len_setup(char *str)
 +{
 +	unsigned size = memparse(str, &str);
 +
 +	if (size)
 +		size = roundup_pow_of_two(size);
 +	if (size > log_buf_len)
 +		new_log_buf_len = size;
 +
 +	return 0;
 +}
 +early_param("log_buf_len", log_buf_len_setup);
 +
 +void __init setup_log_buf(int early)
 +{
 +	unsigned long flags;
 +	char *new_log_buf;
 +	int free;
 +
 +	if (!new_log_buf_len)
 +		return;
 +
 +	if (early) {
 +		unsigned long mem;
 +
 +		mem = memblock_alloc(new_log_buf_len, PAGE_SIZE);
 +		if (!mem)
 +			return;
 +		new_log_buf = __va(mem);
 +	} else {
 +		new_log_buf = alloc_bootmem_nopanic(new_log_buf_len);
 +	}
 +
 +	if (unlikely(!new_log_buf)) {
 +		pr_err("log_buf_len: %ld bytes not available\n",
 +			new_log_buf_len);
 +		return;
 +	}
 +
 +	raw_spin_lock_irqsave(&logbuf_lock, flags);
 +	log_buf_len = new_log_buf_len;
 +	log_buf = new_log_buf;
 +	new_log_buf_len = 0;
 +	free = __LOG_BUF_LEN - log_next_idx;
 +	memcpy(log_buf, __log_buf, __LOG_BUF_LEN);
 +	raw_spin_unlock_irqrestore(&logbuf_lock, flags);
 +
 +	pr_info("log_buf_len: %d\n", log_buf_len);
 +	pr_info("early log buf free: %d(%d%%)\n",
 +		free, (free * 100) / __LOG_BUF_LEN);
 +}
 +
 +static bool __read_mostly ignore_loglevel;
 +
 +static int __init ignore_loglevel_setup(char *str)
 +{
 +	ignore_loglevel = 1;
 +	printk(KERN_INFO "debug: ignoring loglevel setting.\n");
 +
 +	return 0;
 +}
 +
 +early_param("ignore_loglevel", ignore_loglevel_setup);
 +module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR);
 +MODULE_PARM_DESC(ignore_loglevel, "ignore loglevel setting, to"
 +	"print all kernel messages to the console.");
 +
 +#ifdef CONFIG_BOOT_PRINTK_DELAY
 +
 +static int boot_delay; /* msecs delay after each printk during bootup */
 +static unsigned long long loops_per_msec;	/* based on boot_delay */
 +
 +static int __init boot_delay_setup(char *str)
 +{
 +	unsigned long lpj;
 +
 +	lpj = preset_lpj ? preset_lpj : 1000000;	/* some guess */
 +	loops_per_msec = (unsigned long long)lpj / 1000 * HZ;
 +
 +	get_option(&str, &boot_delay);
 +	if (boot_delay > 10 * 1000)
 +		boot_delay = 0;
 +
 +	pr_debug("boot_delay: %u, preset_lpj: %ld, lpj: %lu, "
 +		"HZ: %d, loops_per_msec: %llu\n",
 +		boot_delay, preset_lpj, lpj, HZ, loops_per_msec);
 +	return 1;
 +}
 +__setup("boot_delay=", boot_delay_setup);
 +
 +static void boot_delay_msec(int level)
 +{
 +	unsigned long long k;
 +	unsigned long timeout;
 +
 +	if ((boot_delay == 0 || system_state != SYSTEM_BOOTING)
 +		|| (level >= console_loglevel && !ignore_loglevel)) {
 +		return;
 +	}
 +
 +	k = (unsigned long long)loops_per_msec * boot_delay;
 +
 +	timeout = jiffies + msecs_to_jiffies(boot_delay);
 +	while (k) {
 +		k--;
 +		cpu_relax();
 +		/*
 +		 * use (volatile) jiffies to prevent
 +		 * compiler reduction; loop termination via jiffies
 +		 * is secondary and may or may not happen.
 +		 */
 +		if (time_after(jiffies, timeout))
 +			break;
 +		touch_nmi_watchdog();
 +	}
 +}
 +#else
 +static inline void boot_delay_msec(int level)
 +{
 +}
 +#endif
 +
 +#if defined(CONFIG_PRINTK_TIME)
 +static bool printk_time = 1;
 +#else
 +static bool printk_time;
 +#endif
 +module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR);
 +
 +static size_t print_time(u64 ts, char *buf)
 +{
 +	unsigned long rem_nsec;
 +
 +	if (!printk_time)
 +		return 0;
 +
 +	rem_nsec = do_div(ts, 1000000000);
 +
 +	if (!buf)
 +		return snprintf(NULL, 0, "[%5lu.000000] ", (unsigned long)ts);
 +
 +	return sprintf(buf, "[%5lu.%06lu] ",
 +		       (unsigned long)ts, rem_nsec / 1000);
 +}
 +
 +static size_t print_prefix(const struct printk_log *msg, bool syslog, char *buf)
 +{
 +	size_t len = 0;
 +	unsigned int prefix = (msg->facility << 3) | msg->level;
 +
 +	if (syslog) {
 +		if (buf) {
 +			len += sprintf(buf, "<%u>", prefix);
 +		} else {
 +			len += 3;
 +			if (prefix > 999)
 +				len += 3;
 +			else if (prefix > 99)
 +				len += 2;
 +			else if (prefix > 9)
 +				len++;
 +		}
 +	}
 +
 +	len += print_time(msg->ts_nsec, buf ? buf + len : NULL);
 +	return len;
 +}
 +
 +static size_t msg_print_text(const struct printk_log *msg, enum log_flags prev,
 +			     bool syslog, char *buf, size_t size)
 +{
 +	const char *text = log_text(msg);
 +	size_t text_size = msg->text_len;
 +	bool prefix = true;
 +	bool newline = true;
 +	size_t len = 0;
 +
 +	if ((prev & LOG_CONT) && !(msg->flags & LOG_PREFIX))
 +		prefix = false;
 +
 +	if (msg->flags & LOG_CONT) {
 +		if ((prev & LOG_CONT) && !(prev & LOG_NEWLINE))
 +			prefix = false;
 +
 +		if (!(msg->flags & LOG_NEWLINE))
 +			newline = false;
 +	}
 +
 +	do {
 +		const char *next = memchr(text, '\n', text_size);
 +		size_t text_len;
 +
 +		if (next) {
 +			text_len = next - text;
 +			next++;
 +			text_size -= next - text;
 +		} else {
 +			text_len = text_size;
 +		}
 +
 +		if (buf) {
 +			if (print_prefix(msg, syslog, NULL) +
 +			    text_len + 1 >= size - len)
 +				break;
 +
 +			if (prefix)
 +				len += print_prefix(msg, syslog, buf + len);
 +			memcpy(buf + len, text, text_len);
 +			len += text_len;
 +			if (next || newline)
 +				buf[len++] = '\n';
 +		} else {
 +			/* SYSLOG_ACTION_* buffer size only calculation */
 +			if (prefix)
 +				len += print_prefix(msg, syslog, NULL);
 +			len += text_len;
 +			if (next || newline)
 +				len++;
 +		}
 +
 +		prefix = true;
 +		text = next;
 +	} while (text);
 +
 +	return len;
 +}
 +
 +static int syslog_print(char __user *buf, int size)
 +{
 +	char *text;
 +	struct printk_log *msg;
 +	int len = 0;
 +
 +	text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);
 +	if (!text)
 +		return -ENOMEM;
 +
 +	while (size > 0) {
 +		size_t n;
 +		size_t skip;
 +
 +		raw_spin_lock_irq(&logbuf_lock);
 +		if (syslog_seq < log_first_seq) {
 +			/* messages are gone, move to first one */
 +			syslog_seq = log_first_seq;
 +			syslog_idx = log_first_idx;
 +			syslog_prev = 0;
 +			syslog_partial = 0;
 +		}
 +		if (syslog_seq == log_next_seq) {
 +			raw_spin_unlock_irq(&logbuf_lock);
 +			break;
 +		}
 +
 +		skip = syslog_partial;
 +		msg = log_from_idx(syslog_idx);
 +		n = msg_print_text(msg, syslog_prev, true, text,
 +				   LOG_LINE_MAX + PREFIX_MAX);
 +		if (n - syslog_partial <= size) {
 +			/* message fits into buffer, move forward */
 +			syslog_idx = log_next(syslog_idx);
 +			syslog_seq++;
 +			syslog_prev = msg->flags;
 +			n -= syslog_partial;
 +			syslog_partial = 0;
 +		} else if (!len){
 +			/* partial read(), remember position */
 +			n = size;
 +			syslog_partial += n;
 +		} else
 +			n = 0;
 +		raw_spin_unlock_irq(&logbuf_lock);
 +
 +		if (!n)
 +			break;
 +
 +		if (copy_to_user(buf, text + skip, n)) {
 +			if (!len)
 +				len = -EFAULT;
 +			break;
 +		}
 +
 +		len += n;
 +		size -= n;
 +		buf += n;
 +	}
 +
 +	kfree(text);
 +	return len;
 +}
 +
 +static int syslog_print_all(char __user *buf, int size, bool clear)
 +{
 +	char *text;
 +	int len = 0;
 +
 +	text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);
 +	if (!text)
 +		return -ENOMEM;
 +
 +	raw_spin_lock_irq(&logbuf_lock);
 +	if (buf) {
 +		u64 next_seq;
 +		u64 seq;
 +		u32 idx;
 +		enum log_flags prev;
 +
 +		if (clear_seq < log_first_seq) {
 +			/* messages are gone, move to first available one */
 +			clear_seq = log_first_seq;
 +			clear_idx = log_first_idx;
 +		}
 +
 +		/*
 +		 * Find first record that fits, including all following records,
 +		 * into the user-provided buffer for this dump.
 +		 */
 +		seq = clear_seq;
 +		idx = clear_idx;
 +		prev = 0;
 +		while (seq < log_next_seq) {
 +			struct printk_log *msg = log_from_idx(idx);
 +
 +			len += msg_print_text(msg, prev, true, NULL, 0);
 +			prev = msg->flags;
 +			idx = log_next(idx);
 +			seq++;
 +		}
 +
 +		/* move first record forward until length fits into the buffer */
 +		seq = clear_seq;
 +		idx = clear_idx;
 +		prev = 0;
 +		while (len > size && seq < log_next_seq) {
 +			struct printk_log *msg = log_from_idx(idx);
 +
 +			len -= msg_print_text(msg, prev, true, NULL, 0);
 +			prev = msg->flags;
 +			idx = log_next(idx);
 +			seq++;
 +		}
 +
 +		/* last message fitting into this dump */
 +		next_seq = log_next_seq;
 +
 +		len = 0;
 +		prev = 0;
 +		while (len >= 0 && seq < next_seq) {
 +			struct printk_log *msg = log_from_idx(idx);
 +			int textlen;
 +
 +			textlen = msg_print_text(msg, prev, true, text,
 +						 LOG_LINE_MAX + PREFIX_MAX);
 +			if (textlen < 0) {
 +				len = textlen;
 +				break;
 +			}
 +			idx = log_next(idx);
 +			seq++;
 +			prev = msg->flags;
 +
 +			raw_spin_unlock_irq(&logbuf_lock);
 +			if (copy_to_user(buf + len, text, textlen))
 +				len = -EFAULT;
 +			else
 +				len += textlen;
 +			raw_spin_lock_irq(&logbuf_lock);
 +
 +			if (seq < log_first_seq) {
 +				/* messages are gone, move to next one */
 +				seq = log_first_seq;
 +				idx = log_first_idx;
 +				prev = 0;
 +			}
 +		}
 +	}
 +
 +	if (clear) {
 +		clear_seq = log_next_seq;
 +		clear_idx = log_next_idx;
 +	}
 +	raw_spin_unlock_irq(&logbuf_lock);
 +
 +	kfree(text);
 +	return len;
 +}
 +
 +int do_syslog(int type, char __user *buf, int len, bool from_file)
 +{
 +	bool clear = false;
 +	static int saved_console_loglevel = -1;
 +	int error;
 +
 +	error = check_syslog_permissions(type, from_file);
 +	if (error)
 +		goto out;
 +
 +	error = security_syslog(type);
 +	if (error)
 +		return error;
 +
 +	switch (type) {
 +	case SYSLOG_ACTION_CLOSE:	/* Close log */
 +		break;
 +	case SYSLOG_ACTION_OPEN:	/* Open log */
 +		break;
 +	case SYSLOG_ACTION_READ:	/* Read from log */
 +		error = -EINVAL;
 +		if (!buf || len < 0)
 +			goto out;
 +		error = 0;
 +		if (!len)
 +			goto out;
 +		if (!access_ok(VERIFY_WRITE, buf, len)) {
 +			error = -EFAULT;
 +			goto out;
 +		}
 +		error = wait_event_interruptible(log_wait,
 +						 syslog_seq != log_next_seq);
 +		if (error)
 +			goto out;
 +		error = syslog_print(buf, len);
 +		break;
 +	/* Read/clear last kernel messages */
 +	case SYSLOG_ACTION_READ_CLEAR:
 +		clear = true;
 +		/* FALL THRU */
 +	/* Read last kernel messages */
 +	case SYSLOG_ACTION_READ_ALL:
 +		error = -EINVAL;
 +		if (!buf || len < 0)
 +			goto out;
 +		error = 0;
 +		if (!len)
 +			goto out;
 +		if (!access_ok(VERIFY_WRITE, buf, len)) {
 +			error = -EFAULT;
 +			goto out;
 +		}
 +		error = syslog_print_all(buf, len, clear);
 +		break;
 +	/* Clear ring buffer */
 +	case SYSLOG_ACTION_CLEAR:
 +		syslog_print_all(NULL, 0, true);
 +		break;
 +	/* Disable logging to console */
 +	case SYSLOG_ACTION_CONSOLE_OFF:
 +		if (saved_console_loglevel == -1)
 +			saved_console_loglevel = console_loglevel;
 +		console_loglevel = minimum_console_loglevel;
 +		break;
 +	/* Enable logging to console */
 +	case SYSLOG_ACTION_CONSOLE_ON:
 +		if (saved_console_loglevel != -1) {
 +			console_loglevel = saved_console_loglevel;
 +			saved_console_loglevel = -1;
 +		}
 +		break;
 +	/* Set level of messages printed to console */
 +	case SYSLOG_ACTION_CONSOLE_LEVEL:
 +		error = -EINVAL;
 +		if (len < 1 || len > 8)
 +			goto out;
 +		if (len < minimum_console_loglevel)
 +			len = minimum_console_loglevel;
 +		console_loglevel = len;
 +		/* Implicitly re-enable logging to console */
 +		saved_console_loglevel = -1;
 +		error = 0;
 +		break;
 +	/* Number of chars in the log buffer */
 +	case SYSLOG_ACTION_SIZE_UNREAD:
 +		raw_spin_lock_irq(&logbuf_lock);
 +		if (syslog_seq < log_first_seq) {
 +			/* messages are gone, move to first one */
 +			syslog_seq = log_first_seq;
 +			syslog_idx = log_first_idx;
 +			syslog_prev = 0;
 +			syslog_partial = 0;
 +		}
 +		if (from_file) {
 +			/*
 +			 * Short-cut for poll(/"proc/kmsg") which simply checks
 +			 * for pending data, not the size; return the count of
 +			 * records, not the length.
 +			 */
 +			error = log_next_idx - syslog_idx;
 +		} else {
 +			u64 seq = syslog_seq;
 +			u32 idx = syslog_idx;
 +			enum log_flags prev = syslog_prev;
 +
 +			error = 0;
 +			while (seq < log_next_seq) {
 +				struct printk_log *msg = log_from_idx(idx);
 +
 +				error += msg_print_text(msg, prev, true, NULL, 0);
 +				idx = log_next(idx);
 +				seq++;
 +				prev = msg->flags;
 +			}
 +			error -= syslog_partial;
 +		}
 +		raw_spin_unlock_irq(&logbuf_lock);
 +		break;
 +	/* Size of the log buffer */
 +	case SYSLOG_ACTION_SIZE_BUFFER:
 +		error = log_buf_len;
 +		break;
 +	default:
 +		error = -EINVAL;
 +		break;
 +	}
 +out:
 +	return error;
 +}
 +
 +SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len)
 +{
 +	return do_syslog(type, buf, len, SYSLOG_FROM_READER);
 +}
 +
 +/*
 + * Call the console drivers, asking them to write out
 + * log_buf[start] to log_buf[end - 1].
 + * The console_lock must be held.
 + */
 +static void call_console_drivers(int level, const char *text, size_t len)
 +{
 +	struct console *con;
 +
 +	trace_console(text, len);
 +
- 	if (level >= console_loglevel && !ignore_loglevel)
- 		return;
 +	if (!console_drivers)
 +		return;
 +
 +	for_each_console(con) {
 +		if (exclusive_console && con != exclusive_console)
 +			continue;
 +		if (!(con->flags & CON_ENABLED))
 +			continue;
 +		if (!con->write)
 +			continue;
 +		if (!cpu_online(smp_processor_id()) &&
 +		    !(con->flags & CON_ANYTIME))
 +			continue;
++		if (level >= console_loglevel && !ignore_loglevel &&
++		    !(con->flags & CON_ALLDATA))
++			continue;
 +		con->write(con, text, len);
 +	}
 +}
 +
 +/*
 + * Zap console related locks when oopsing. Only zap at most once
 + * every 10 seconds, to leave time for slow consoles to print a
 + * full oops.
 + */
 +static void zap_locks(void)
 +{
 +	static unsigned long oops_timestamp;
 +
 +	if (time_after_eq(jiffies, oops_timestamp) &&
 +			!time_after(jiffies, oops_timestamp + 30 * HZ))
 +		return;
 +
 +	oops_timestamp = jiffies;
 +
 +	debug_locks_off();
 +	/* If a crash is occurring, make sure we can't deadlock */
 +	raw_spin_lock_init(&logbuf_lock);
 +	/* And make sure that we print immediately */
 +	sema_init(&console_sem, 1);
 +}
 +
 +/* Check if we have any console registered that can be called early in boot. */
 +static int have_callable_console(void)
 +{
 +	struct console *con;
 +
 +	for_each_console(con)
 +		if (con->flags & CON_ANYTIME)
 +			return 1;
 +
 +	return 0;
 +}
 +
 +/*
 + * Can we actually use the console at this time on this cpu?
 + *
 + * Console drivers may assume that per-cpu resources have
 + * been allocated. So unless they're explicitly marked as
 + * being able to cope (CON_ANYTIME) don't call them until
 + * this CPU is officially up.
 + */
 +static inline int can_use_console(unsigned int cpu)
 +{
 +	return cpu_online(cpu) || have_callable_console();
 +}
 +
 +/*
 + * Try to get console ownership to actually show the kernel
 + * messages from a 'printk'. Return true (and with the
 + * console_lock held, and 'console_locked' set) if it
 + * is successful, false otherwise.
 + *
 + * This gets called with the 'logbuf_lock' spinlock held and
 + * interrupts disabled. It should return with 'lockbuf_lock'
 + * released but interrupts still disabled.
 + */
 +static int console_trylock_for_printk(unsigned int cpu)
 +	__releases(&logbuf_lock)
 +{
 +	int retval = 0, wake = 0;
 +
 +	if (console_trylock()) {
 +		retval = 1;
 +
 +		/*
 +		 * If we can't use the console, we need to release
 +		 * the console semaphore by hand to avoid flushing
 +		 * the buffer. We need to hold the console semaphore
 +		 * in order to do this test safely.
 +		 */
 +		if (!can_use_console(cpu)) {
 +			console_locked = 0;
 +			wake = 1;
 +			retval = 0;
 +		}
 +	}
 +	logbuf_cpu = UINT_MAX;
 +	raw_spin_unlock(&logbuf_lock);
 +	if (wake)
 +		up(&console_sem);
 +	return retval;
 +}
 +
 +int printk_delay_msec __read_mostly;
 +
 +static inline void printk_delay(void)
 +{
 +	if (unlikely(printk_delay_msec)) {
 +		int m = printk_delay_msec;
 +
 +		while (m--) {
 +			mdelay(1);
 +			touch_nmi_watchdog();
 +		}
 +	}
 +}
 +
 +/*
 + * Continuation lines are buffered, and not committed to the record buffer
 + * until the line is complete, or a race forces it. The line fragments
 + * though, are printed immediately to the consoles to ensure everything has
 + * reached the console in case of a kernel crash.
 + */
 +static struct cont {
 +	char buf[LOG_LINE_MAX];
 +	size_t len;			/* length == 0 means unused buffer */
 +	size_t cons;			/* bytes written to console */
 +	struct task_struct *owner;	/* task of first print*/
 +	u64 ts_nsec;			/* time of first print */
 +	u8 level;			/* log level of first message */
 +	u8 facility;			/* log level of first message */
 +	enum log_flags flags;		/* prefix, newline flags */
 +	bool flushed:1;			/* buffer sealed and committed */
 +} cont;
 +
 +static void cont_flush(enum log_flags flags)
 +{
 +	if (cont.flushed)
 +		return;
 +	if (cont.len == 0)
 +		return;
 +
 +	if (cont.cons) {
 +		/*
 +		 * If a fragment of this line was directly flushed to the
 +		 * console; wait for the console to pick up the rest of the
 +		 * line. LOG_NOCONS suppresses a duplicated output.
 +		 */
 +		log_store(cont.facility, cont.level, flags | LOG_NOCONS,
 +			  cont.ts_nsec, NULL, 0, cont.buf, cont.len);
 +		cont.flags = flags;
 +		cont.flushed = true;
 +	} else {
 +		/*
 +		 * If no fragment of this line ever reached the console,
 +		 * just submit it to the store and free the buffer.
 +		 */
 +		log_store(cont.facility, cont.level, flags, 0,
 +			  NULL, 0, cont.buf, cont.len);
 +		cont.len = 0;
 +	}
 +}
 +
 +static bool cont_add(int facility, int level, const char *text, size_t len)
 +{
 +	if (cont.len && cont.flushed)
 +		return false;
 +
 +	if (cont.len + len > sizeof(cont.buf)) {
 +		/* the line gets too long, split it up in separate records */
 +		cont_flush(LOG_CONT);
 +		return false;
 +	}
 +
 +	if (!cont.len) {
 +		cont.facility = facility;
 +		cont.level = level;
 +		cont.owner = current;
 +		cont.ts_nsec = local_clock();
 +		cont.flags = 0;
 +		cont.cons = 0;
 +		cont.flushed = false;
 +	}
 +
 +	memcpy(cont.buf + cont.len, text, len);
 +	cont.len += len;
 +
 +	if (cont.len > (sizeof(cont.buf) * 80) / 100)
 +		cont_flush(LOG_CONT);
 +
 +	return true;
 +}
 +
 +static size_t cont_print_text(char *text, size_t size)
 +{
 +	size_t textlen = 0;
 +	size_t len;
 +
 +	if (cont.cons == 0 && (console_prev & LOG_NEWLINE)) {
 +		textlen += print_time(cont.ts_nsec, text);
 +		size -= textlen;
 +	}
 +
 +	len = cont.len - cont.cons;
 +	if (len > 0) {
 +		if (len+1 > size)
 +			len = size-1;
 +		memcpy(text + textlen, cont.buf + cont.cons, len);
 +		textlen += len;
 +		cont.cons = cont.len;
 +	}
 +
 +	if (cont.flushed) {
 +		if (cont.flags & LOG_NEWLINE)
 +			text[textlen++] = '\n';
 +		/* got everything, release buffer */
 +		cont.len = 0;
 +	}
 +	return textlen;
 +}
 +
 +asmlinkage int vprintk_emit(int facility, int level,
 +			    const char *dict, size_t dictlen,
 +			    const char *fmt, va_list args)
 +{
 +	static int recursion_bug;
 +	static char textbuf[LOG_LINE_MAX];
 +	char *text = textbuf;
 +	size_t text_len;
 +	enum log_flags lflags = 0;
 +	unsigned long flags;
 +	int this_cpu;
 +	int printed_len = 0;
 +
 +	boot_delay_msec(level);
 +	printk_delay();
 +
 +	/* This stops the holder of console_sem just where we want him */
 +	local_irq_save(flags);
 +	this_cpu = smp_processor_id();
 +
 +	/*
 +	 * Ouch, printk recursed into itself!
 +	 */
 +	if (unlikely(logbuf_cpu == this_cpu)) {
 +		/*
 +		 * If a crash is occurring during printk() on this CPU,
 +		 * then try to get the crash message out but make sure
 +		 * we can't deadlock. Otherwise just return to avoid the
 +		 * recursion and return - but flag the recursion so that
 +		 * it can be printed at the next appropriate moment:
 +		 */
 +		if (!oops_in_progress && !lockdep_recursing(current)) {
 +			recursion_bug = 1;
 +			goto out_restore_irqs;
 +		}
 +		zap_locks();
 +	}
 +
 +	lockdep_off();
 +	raw_spin_lock(&logbuf_lock);
 +	logbuf_cpu = this_cpu;
 +
 +	if (recursion_bug) {
 +		static const char recursion_msg[] =
 +			"BUG: recent printk recursion!";
 +
 +		recursion_bug = 0;
 +		printed_len += strlen(recursion_msg);
 +		/* emit KERN_CRIT message */
 +		log_store(0, 2, LOG_PREFIX|LOG_NEWLINE, 0,
 +			  NULL, 0, recursion_msg, printed_len);
 +	}
 +
 +	/*
 +	 * The printf needs to come first; we need the syslog
 +	 * prefix which might be passed-in as a parameter.
 +	 */
 +	text_len = vscnprintf(text, sizeof(textbuf), fmt, args);
 +
 +	/* mark and strip a trailing newline */
 +	if (text_len && text[text_len-1] == '\n') {
 +		text_len--;
 +		lflags |= LOG_NEWLINE;
 +	}
 +
 +	/* strip kernel syslog prefix and extract log level or control flags */
 +	if (facility == 0) {
 +		int kern_level = printk_get_level(text);
 +
 +		if (kern_level) {
 +			const char *end_of_header = printk_skip_level(text);
 +			switch (kern_level) {
 +			case '0' ... '7':
 +				if (level == -1)
 +					level = kern_level - '0';
 +			case 'd':	/* KERN_DEFAULT */
 +				lflags |= LOG_PREFIX;
 +			case 'c':	/* KERN_CONT */
 +				break;
 +			}
 +			text_len -= end_of_header - text;
 +			text = (char *)end_of_header;
 +		}
 +	}
 +
 +	if (level == -1)
 +		level = default_message_loglevel;
 +
 +	if (dict)
 +		lflags |= LOG_PREFIX|LOG_NEWLINE;
 +
 +	if (!(lflags & LOG_NEWLINE)) {
 +		/*
 +		 * Flush the conflicting buffer. An earlier newline was missing,
 +		 * or another task also prints continuation lines.
 +		 */
 +		if (cont.len && (lflags & LOG_PREFIX || cont.owner != current))
 +			cont_flush(LOG_NEWLINE);
 +
 +		/* buffer line if possible, otherwise store it right away */
 +		if (!cont_add(facility, level, text, text_len))
 +			log_store(facility, level, lflags | LOG_CONT, 0,
 +				  dict, dictlen, text, text_len);
 +	} else {
 +		bool stored = false;
 +
 +		/*
 +		 * If an earlier newline was missing and it was the same task,
 +		 * either merge it with the current buffer and flush, or if
 +		 * there was a race with interrupts (prefix == true) then just
 +		 * flush it out and store this line separately.
 +		 */
 +		if (cont.len && cont.owner == current) {
 +			if (!(lflags & LOG_PREFIX))
 +				stored = cont_add(facility, level, text, text_len);
 +			cont_flush(LOG_NEWLINE);
 +		}
 +
 +		if (!stored)
 +			log_store(facility, level, lflags, 0,
 +				  dict, dictlen, text, text_len);
 +	}
 +	printed_len += text_len;
 +
 +	/*
 +	 * Try to acquire and then immediately release the console semaphore.
 +	 * The release will print out buffers and wake up /dev/kmsg and syslog()
 +	 * users.
 +	 *
 +	 * The console_trylock_for_printk() function will release 'logbuf_lock'
 +	 * regardless of whether it actually gets the console semaphore or not.
 +	 */
 +	if (console_trylock_for_printk(this_cpu))
 +		console_unlock();
 +
 +	lockdep_on();
 +out_restore_irqs:
 +	local_irq_restore(flags);
 +
 +	return printed_len;
 +}
 +EXPORT_SYMBOL(vprintk_emit);
 +
 +asmlinkage int vprintk(const char *fmt, va_list args)
 +{
 +	return vprintk_emit(0, -1, NULL, 0, fmt, args);
 +}
 +EXPORT_SYMBOL(vprintk);
 +
 +asmlinkage int printk_emit(int facility, int level,
 +			   const char *dict, size_t dictlen,
 +			   const char *fmt, ...)
 +{
 +	va_list args;
 +	int r;
 +
 +	va_start(args, fmt);
 +	r = vprintk_emit(facility, level, dict, dictlen, fmt, args);
 +	va_end(args);
 +
 +	return r;
 +}
 +EXPORT_SYMBOL(printk_emit);
 +
 +/**
 + * printk - print a kernel message
 + * @fmt: format string
 + *
 + * This is printk(). It can be called from any context. We want it to work.
 + *
 + * We try to grab the console_lock. If we succeed, it's easy - we log the
 + * output and call the console drivers.  If we fail to get the semaphore, we
 + * place the output into the log buffer and return. The current holder of
 + * the console_sem will notice the new output in console_unlock(); and will
 + * send it to the consoles before releasing the lock.
 + *
 + * One effect of this deferred printing is that code which calls printk() and
 + * then changes console_loglevel may break. This is because console_loglevel
 + * is inspected when the actual printing occurs.
 + *
 + * See also:
 + * printf(3)
 + *
 + * See the vsnprintf() documentation for format string extensions over C99.
 + */
 +asmlinkage int printk(const char *fmt, ...)
 +{
 +	va_list args;
 +	int r;
 +
 +#ifdef CONFIG_KGDB_KDB
 +	if (unlikely(kdb_trap_printk)) {
 +		va_start(args, fmt);
 +		r = vkdb_printf(fmt, args);
 +		va_end(args);
 +		return r;
 +	}
 +#endif
 +	va_start(args, fmt);
 +	r = vprintk_emit(0, -1, NULL, 0, fmt, args);
 +	va_end(args);
 +
 +	return r;
 +}
 +EXPORT_SYMBOL(printk);
 +
 +#else /* CONFIG_PRINTK */
 +
 +#define LOG_LINE_MAX		0
 +#define PREFIX_MAX		0
 +#define LOG_LINE_MAX 0
 +static u64 syslog_seq;
 +static u32 syslog_idx;
 +static u64 console_seq;
 +static u32 console_idx;
 +static enum log_flags syslog_prev;
 +static u64 log_first_seq;
 +static u32 log_first_idx;
 +static u64 log_next_seq;
 +static enum log_flags console_prev;
 +static struct cont {
 +	size_t len;
 +	size_t cons;
 +	u8 level;
 +	bool flushed:1;
 +} cont;
 +static struct printk_log *log_from_idx(u32 idx) { return NULL; }
 +static u32 log_next(u32 idx) { return 0; }
 +static void call_console_drivers(int level, const char *text, size_t len) {}
 +static size_t msg_print_text(const struct printk_log *msg, enum log_flags prev,
 +			     bool syslog, char *buf, size_t size) { return 0; }
 +static size_t cont_print_text(char *text, size_t size) { return 0; }
 +
 +#endif /* CONFIG_PRINTK */
 +
 +#ifdef CONFIG_EARLY_PRINTK
 +struct console *early_console;
 +
 +void early_vprintk(const char *fmt, va_list ap)
 +{
 +	if (early_console) {
 +		char buf[512];
 +		int n = vscnprintf(buf, sizeof(buf), fmt, ap);
 +
 +		early_console->write(early_console, buf, n);
 +	}
 +}
 +
 +asmlinkage void early_printk(const char *fmt, ...)
 +{
 +	va_list ap;
 +
 +	va_start(ap, fmt);
 +	early_vprintk(fmt, ap);
 +	va_end(ap);
 +}
 +#endif
 +
 +static int __add_preferred_console(char *name, int idx, char *options,
 +				   char *brl_options)
 +{
 +	struct console_cmdline *c;
 +	int i;
 +
 +	/*
 +	 *	See if this tty is not yet registered, and
 +	 *	if we have a slot free.
 +	 */
 +	for (i = 0, c = console_cmdline;
 +	     i < MAX_CMDLINECONSOLES && c->name[0];
 +	     i++, c++) {
 +		if (strcmp(c->name, name) == 0 && c->index == idx) {
 +			if (!brl_options)
 +				selected_console = i;
 +			return 0;
 +		}
 +	}
 +	if (i == MAX_CMDLINECONSOLES)
 +		return -E2BIG;
 +	if (!brl_options)
 +		selected_console = i;
 +	strlcpy(c->name, name, sizeof(c->name));
 +	c->options = options;
 +	braille_set_options(c, brl_options);
 +
 +	c->index = idx;
 +	return 0;
 +}
 +/*
 + * Set up a list of consoles.  Called from init/main.c
 + */
 +static int __init console_setup(char *str)
 +{
 +	char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for index */
 +	char *s, *options, *brl_options = NULL;
 +	int idx;
 +
 +	if (_braille_console_setup(&str, &brl_options))
 +		return 1;
 +
 +	/*
 +	 * Decode str into name, index, options.
 +	 */
 +	if (str[0] >= '0' && str[0] <= '9') {
 +		strcpy(buf, "ttyS");
 +		strncpy(buf + 4, str, sizeof(buf) - 5);
 +	} else {
 +		strncpy(buf, str, sizeof(buf) - 1);
 +	}
 +	buf[sizeof(buf) - 1] = 0;
 +	if ((options = strchr(str, ',')) != NULL)
 +		*(options++) = 0;
 +#ifdef __sparc__
 +	if (!strcmp(str, "ttya"))
 +		strcpy(buf, "ttyS0");
 +	if (!strcmp(str, "ttyb"))
 +		strcpy(buf, "ttyS1");
 +#endif
 +	for (s = buf; *s; s++)
 +		if ((*s >= '0' && *s <= '9') || *s == ',')
 +			break;
 +	idx = simple_strtoul(s, NULL, 10);
 +	*s = 0;
 +
 +	__add_preferred_console(buf, idx, options, brl_options);
 +	console_set_on_cmdline = 1;
 +	return 1;
 +}
 +__setup("console=", console_setup);
 +
 +/**
 + * add_preferred_console - add a device to the list of preferred consoles.
 + * @name: device name
 + * @idx: device index
 + * @options: options for this console
 + *
 + * The last preferred console added will be used for kernel messages
 + * and stdin/out/err for init.  Normally this is used by console_setup
 + * above to handle user-supplied console arguments; however it can also
 + * be used by arch-specific code either to override the user or more
 + * commonly to provide a default console (ie from PROM variables) when
 + * the user has not supplied one.
 + */
 +int add_preferred_console(char *name, int idx, char *options)
 +{
 +	return __add_preferred_console(name, idx, options, NULL);
 +}
 +
 +int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options)
 +{
 +	struct console_cmdline *c;
 +	int i;
 +
 +	for (i = 0, c = console_cmdline;
 +	     i < MAX_CMDLINECONSOLES && c->name[0];
 +	     i++, c++)
 +		if (strcmp(c->name, name) == 0 && c->index == idx) {
 +			strlcpy(c->name, name_new, sizeof(c->name));
 +			c->name[sizeof(c->name) - 1] = 0;
 +			c->options = options;
 +			c->index = idx_new;
 +			return i;
 +		}
 +	/* not found */
 +	return -1;
 +}
 +
 +bool console_suspend_enabled = 1;
 +EXPORT_SYMBOL(console_suspend_enabled);
 +
 +static int __init console_suspend_disable(char *str)
 +{
 +	console_suspend_enabled = 0;
 +	return 1;
 +}
 +__setup("no_console_suspend", console_suspend_disable);
 +module_param_named(console_suspend, console_suspend_enabled,
 +		bool, S_IRUGO | S_IWUSR);
 +MODULE_PARM_DESC(console_suspend, "suspend console during suspend"
 +	" and hibernate operations");
 +
 +/**
 + * suspend_console - suspend the console subsystem
 + *
 + * This disables printk() while we go into suspend states
 + */
 +void suspend_console(void)
 +{
 +	if (!console_suspend_enabled)
 +		return;
 +	printk("Suspending console(s) (use no_console_suspend to debug)\n");
 +	console_lock();
 +	console_suspended = 1;
 +	up(&console_sem);
 +}
 +
 +void resume_console(void)
 +{
 +	if (!console_suspend_enabled)
 +		return;
 +	down(&console_sem);
 +	console_suspended = 0;
 +	console_unlock();
 +}
 +
 +/**
 + * console_cpu_notify - print deferred console messages after CPU hotplug
 + * @self: notifier struct
 + * @action: CPU hotplug event
 + * @hcpu: unused
 + *
 + * If printk() is called from a CPU that is not online yet, the messages
 + * will be spooled but will not show up on the console.  This function is
 + * called when a new CPU comes online (or fails to come up), and ensures
 + * that any such output gets printed.
 + */
 +static int console_cpu_notify(struct notifier_block *self,
 +	unsigned long action, void *hcpu)
 +{
 +	switch (action) {
 +	case CPU_ONLINE:
 +	case CPU_DEAD:
 +	case CPU_DOWN_FAILED:
 +	case CPU_UP_CANCELED:
 +		console_lock();
 +		console_unlock();
 +	}
 +	return NOTIFY_OK;
 +}
 +
 +/**
 + * console_lock - lock the console system for exclusive use.
 + *
 + * Acquires a lock which guarantees that the caller has
 + * exclusive access to the console system and the console_drivers list.
 + *
 + * Can sleep, returns nothing.
 + */
 +void console_lock(void)
 +{
 +	might_sleep();
 +
 +	down(&console_sem);
 +	if (console_suspended)
 +		return;
 +	console_locked = 1;
 +	console_may_schedule = 1;
 +	mutex_acquire(&console_lock_dep_map, 0, 0, _RET_IP_);
 +}
 +EXPORT_SYMBOL(console_lock);
 +
 +/**
 + * console_trylock - try to lock the console system for exclusive use.
 + *
 + * Tried to acquire a lock which guarantees that the caller has
 + * exclusive access to the console system and the console_drivers list.
 + *
 + * returns 1 on success, and 0 on failure to acquire the lock.
 + */
 +int console_trylock(void)
 +{
 +	if (down_trylock(&console_sem))
 +		return 0;
 +	if (console_suspended) {
 +		up(&console_sem);
 +		return 0;
 +	}
 +	console_locked = 1;
 +	console_may_schedule = 0;
 +	mutex_acquire(&console_lock_dep_map, 0, 1, _RET_IP_);
 +	return 1;
 +}
 +EXPORT_SYMBOL(console_trylock);
 +
 +int is_console_locked(void)
 +{
 +	return console_locked;
 +}
 +
 +static void console_cont_flush(char *text, size_t size)
 +{
 +	unsigned long flags;
 +	size_t len;
 +
 +	raw_spin_lock_irqsave(&logbuf_lock, flags);
 +
 +	if (!cont.len)
 +		goto out;
 +
 +	/*
 +	 * We still queue earlier records, likely because the console was
 +	 * busy. The earlier ones need to be printed before this one, we
 +	 * did not flush any fragment so far, so just let it queue up.
 +	 */
 +	if (console_seq < log_next_seq && !cont.cons)
 +		goto out;
 +
 +	len = cont_print_text(text, size);
 +	raw_spin_unlock(&logbuf_lock);
 +	stop_critical_timings();
 +	call_console_drivers(cont.level, text, len);
 +	start_critical_timings();
 +	local_irq_restore(flags);
 +	return;
 +out:
 +	raw_spin_unlock_irqrestore(&logbuf_lock, flags);
 +}
 +
 +/**
 + * console_unlock - unlock the console system
 + *
 + * Releases the console_lock which the caller holds on the console system
 + * and the console driver list.
 + *
 + * While the console_lock was held, console output may have been buffered
 + * by printk().  If this is the case, console_unlock(); emits
 + * the output prior to releasing the lock.
 + *
 + * If there is output waiting, we wake /dev/kmsg and syslog() users.
 + *
 + * console_unlock(); may be called from any context.
 + */
 +void console_unlock(void)
 +{
 +	static char text[LOG_LINE_MAX + PREFIX_MAX];
 +	static u64 seen_seq;
 +	unsigned long flags;
 +	bool wake_klogd = false;
 +	bool retry;
 +
 +	if (console_suspended) {
 +		up(&console_sem);
 +		return;
 +	}
 +
 +	console_may_schedule = 0;
 +
 +	/* flush buffered message fragment immediately to console */
 +	console_cont_flush(text, sizeof(text));
 +again:
 +	for (;;) {
 +		struct printk_log *msg;
 +		size_t len;
 +		int level;
 +
 +		raw_spin_lock_irqsave(&logbuf_lock, flags);
 +		if (seen_seq != log_next_seq) {
 +			wake_klogd = true;
 +			seen_seq = log_next_seq;
 +		}
 +
 +		if (console_seq < log_first_seq) {
 +			/* messages are gone, move to first one */
 +			console_seq = log_first_seq;
 +			console_idx = log_first_idx;
 +			console_prev = 0;
 +		}
 +skip:
 +		if (console_seq == log_next_seq)
 +			break;
 +
 +		msg = log_from_idx(console_idx);
 +		if (msg->flags & LOG_NOCONS) {
 +			/*
 +			 * Skip record we have buffered and already printed
 +			 * directly to the console when we received it.
 +			 */
 +			console_idx = log_next(console_idx);
 +			console_seq++;
 +			/*
 +			 * We will get here again when we register a new
 +			 * CON_PRINTBUFFER console. Clear the flag so we
 +			 * will properly dump everything later.
 +			 */
 +			msg->flags &= ~LOG_NOCONS;
 +			console_prev = msg->flags;
 +			goto skip;
 +		}
 +
 +		level = msg->level;
 +		len = msg_print_text(msg, console_prev, false,
 +				     text, sizeof(text));
 +		console_idx = log_next(console_idx);
 +		console_seq++;
 +		console_prev = msg->flags;
 +		raw_spin_unlock(&logbuf_lock);
 +
 +		stop_critical_timings();	/* don't trace print latency */
 +		call_console_drivers(level, text, len);
 +		start_critical_timings();
 +		local_irq_restore(flags);
 +	}
 +	console_locked = 0;
 +	mutex_release(&console_lock_dep_map, 1, _RET_IP_);
 +
 +	/* Release the exclusive_console once it is used */
 +	if (unlikely(exclusive_console))
 +		exclusive_console = NULL;
 +
 +	raw_spin_unlock(&logbuf_lock);
 +
 +	up(&console_sem);
 +
 +	/*
 +	 * Someone could have filled up the buffer again, so re-check if there's
 +	 * something to flush. In case we cannot trylock the console_sem again,
 +	 * there's a new owner and the console_unlock() from them will do the
 +	 * flush, no worries.
 +	 */
 +	raw_spin_lock(&logbuf_lock);
 +	retry = console_seq != log_next_seq;
 +	raw_spin_unlock_irqrestore(&logbuf_lock, flags);
 +
 +	if (retry && console_trylock())
 +		goto again;
 +
 +	if (wake_klogd)
 +		wake_up_klogd();
 +}
 +EXPORT_SYMBOL(console_unlock);
 +
 +/**
 + * console_conditional_schedule - yield the CPU if required
 + *
 + * If the console code is currently allowed to sleep, and
 + * if this CPU should yield the CPU to another task, do
 + * so here.
 + *
 + * Must be called within console_lock();.
 + */
 +void __sched console_conditional_schedule(void)
 +{
 +	if (console_may_schedule)
 +		cond_resched();
 +}
 +EXPORT_SYMBOL(console_conditional_schedule);
 +
 +void console_unblank(void)
 +{
 +	struct console *c;
 +
 +	/*
 +	 * console_unblank can no longer be called in interrupt context unless
 +	 * oops_in_progress is set to 1..
 +	 */
 +	if (oops_in_progress) {
 +		if (down_trylock(&console_sem) != 0)
 +			return;
 +	} else
 +		console_lock();
 +
 +	console_locked = 1;
 +	console_may_schedule = 0;
 +	for_each_console(c)
 +		if ((c->flags & CON_ENABLED) && c->unblank)
 +			c->unblank();
 +	console_unlock();
 +}
 +
 +/*
 + * Return the console tty driver structure and its associated index
 + */
 +struct tty_driver *console_device(int *index)
 +{
 +	struct console *c;
 +	struct tty_driver *driver = NULL;
 +
 +	console_lock();
 +	for_each_console(c) {
 +		if (!c->device)
 +			continue;
 +		driver = c->device(c, index);
 +		if (driver)
 +			break;
 +	}
 +	console_unlock();
 +	return driver;
 +}
 +
 +/*
 + * Prevent further output on the passed console device so that (for example)
 + * serial drivers can disable console output before suspending a port, and can
 + * re-enable output afterwards.
 + */
 +void console_stop(struct console *console)
 +{
 +	console_lock();
 +	console->flags &= ~CON_ENABLED;
 +	console_unlock();
 +}
 +EXPORT_SYMBOL(console_stop);
 +
 +void console_start(struct console *console)
 +{
 +	console_lock();
 +	console->flags |= CON_ENABLED;
 +	console_unlock();
 +}
 +EXPORT_SYMBOL(console_start);
 +
 +static int __read_mostly keep_bootcon;
 +
 +static int __init keep_bootcon_setup(char *str)
 +{
 +	keep_bootcon = 1;
 +	printk(KERN_INFO "debug: skip boot console de-registration.\n");
 +
 +	return 0;
 +}
 +
 +early_param("keep_bootcon", keep_bootcon_setup);
 +
 +/*
 + * The console driver calls this routine during kernel initialization
 + * to register the console printing procedure with printk() and to
 + * print any messages that were printed by the kernel before the
 + * console driver was initialized.
 + *
 + * This can happen pretty early during the boot process (because of
 + * early_printk) - sometimes before setup_arch() completes - be careful
 + * of what kernel features are used - they may not be initialised yet.
 + *
 + * There are two types of consoles - bootconsoles (early_printk) and
 + * "real" consoles (everything which is not a bootconsole) which are
 + * handled differently.
 + *  - Any number of bootconsoles can be registered at any time.
 + *  - As soon as a "real" console is registered, all bootconsoles
 + *    will be unregistered automatically.
 + *  - Once a "real" console is registered, any attempt to register a
 + *    bootconsoles will be rejected
 + */
 +void register_console(struct console *newcon)
 +{
 +	int i;
 +	unsigned long flags;
 +	struct console *bcon = NULL;
 +	struct console_cmdline *c;
 +
 +	if (console_drivers)
 +		for_each_console(bcon)
 +			if (WARN(bcon == newcon,
 +					"console '%s%d' already registered\n",
 +					bcon->name, bcon->index))
 +				return;
 +
 +	/*
 +	 * before we register a new CON_BOOT console, make sure we don't
 +	 * already have a valid console
 +	 */
 +	if (console_drivers && newcon->flags & CON_BOOT) {
 +		/* find the last or real console */
 +		for_each_console(bcon) {
 +			if (!(bcon->flags & CON_BOOT)) {
 +				printk(KERN_INFO "Too late to register bootconsole %s%d\n",
 +					newcon->name, newcon->index);
 +				return;
 +			}
 +		}
 +	}
 +
 +	if (console_drivers && console_drivers->flags & CON_BOOT)
 +		bcon = console_drivers;
 +
 +	if (preferred_console < 0 || bcon || !console_drivers)
 +		preferred_console = selected_console;
 +
 +	if (newcon->early_setup)
 +		newcon->early_setup();
 +
 +	/*
 +	 *	See if we want to use this console driver. If we
 +	 *	didn't select a console we take the first one
 +	 *	that registers here.
 +	 */
 +	if (preferred_console < 0) {
 +		if (newcon->index < 0)
 +			newcon->index = 0;
 +		if (newcon->setup == NULL ||
 +		    newcon->setup(newcon, NULL) == 0) {
 +			newcon->flags |= CON_ENABLED;
 +			if (newcon->device) {
 +				newcon->flags |= CON_CONSDEV;
 +				preferred_console = 0;
 +			}
 +		}
 +	}
 +
 +	/*
 +	 *	See if this console matches one we selected on
 +	 *	the command line.
 +	 */
 +	for (i = 0, c = console_cmdline;
 +	     i < MAX_CMDLINECONSOLES && c->name[0];
 +	     i++, c++) {
 +		if (strcmp(c->name, newcon->name) != 0)
 +			continue;
 +		if (newcon->index >= 0 &&
 +		    newcon->index != c->index)
 +			continue;
 +		if (newcon->index < 0)
 +			newcon->index = c->index;
 +
 +		if (_braille_register_console(newcon, c))
 +			return;
 +
 +		if (newcon->setup &&
 +		    newcon->setup(newcon, console_cmdline[i].options) != 0)
 +			break;
 +		newcon->flags |= CON_ENABLED;
 +		newcon->index = c->index;
 +		if (i == selected_console) {
 +			newcon->flags |= CON_CONSDEV;
 +			preferred_console = selected_console;
 +		}
 +		break;
 +	}
 +
 +	if (!(newcon->flags & CON_ENABLED))
 +		return;
 +
 +	/*
 +	 * If we have a bootconsole, and are switching to a real console,
 +	 * don't print everything out again, since when the boot console, and
 +	 * the real console are the same physical device, it's annoying to
 +	 * see the beginning boot messages twice
 +	 */
 +	if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV))
 +		newcon->flags &= ~CON_PRINTBUFFER;
 +
 +	/*
 +	 *	Put this console in the list - keep the
 +	 *	preferred driver at the head of the list.
 +	 */
 +	console_lock();
 +	if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) {
 +		newcon->next = console_drivers;
 +		console_drivers = newcon;
 +		if (newcon->next)
 +			newcon->next->flags &= ~CON_CONSDEV;
 +	} else {
 +		newcon->next = console_drivers->next;
 +		console_drivers->next = newcon;
 +	}
 +	if (newcon->flags & CON_PRINTBUFFER) {
 +		/*
 +		 * console_unlock(); will print out the buffered messages
 +		 * for us.
 +		 */
 +		raw_spin_lock_irqsave(&logbuf_lock, flags);
 +		console_seq = syslog_seq;
 +		console_idx = syslog_idx;
 +		console_prev = syslog_prev;
 +		raw_spin_unlock_irqrestore(&logbuf_lock, flags);
 +		/*
 +		 * We're about to replay the log buffer.  Only do this to the
 +		 * just-registered console to avoid excessive message spam to
 +		 * the already-registered consoles.
 +		 */
 +		exclusive_console = newcon;
 +	}
 +	console_unlock();
 +	console_sysfs_notify();
 +
 +	/*
 +	 * By unregistering the bootconsoles after we enable the real console
 +	 * we get the "console xxx enabled" message on all the consoles -
 +	 * boot consoles, real consoles, etc - this is to ensure that end
 +	 * users know there might be something in the kernel's log buffer that
 +	 * went to the bootconsole (that they do not see on the real console)
 +	 */
 +	if (bcon &&
 +	    ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) &&
 +	    !keep_bootcon) {
 +		/* we need to iterate through twice, to make sure we print
 +		 * everything out, before we unregister the console(s)
 +		 */
 +		printk(KERN_INFO "console [%s%d] enabled, bootconsole disabled\n",
 +			newcon->name, newcon->index);
 +		for_each_console(bcon)
 +			if (bcon->flags & CON_BOOT)
 +				unregister_console(bcon);
 +	} else {
 +		printk(KERN_INFO "%sconsole [%s%d] enabled\n",
 +			(newcon->flags & CON_BOOT) ? "boot" : "" ,
 +			newcon->name, newcon->index);
 +	}
 +}
 +EXPORT_SYMBOL(register_console);
 +
 +int unregister_console(struct console *console)
 +{
 +        struct console *a, *b;
 +	int res;
 +
 +	res = _braille_unregister_console(console);
 +	if (res)
 +		return res;
 +
 +	res = 1;
 +	console_lock();
 +	if (console_drivers == console) {
 +		console_drivers=console->next;
 +		res = 0;
 +	} else if (console_drivers) {
 +		for (a=console_drivers->next, b=console_drivers ;
 +		     a; b=a, a=b->next) {
 +			if (a == console) {
 +				b->next = a->next;
 +				res = 0;
 +				break;
 +			}
 +		}
 +	}
 +
 +	/*
 +	 * If this isn't the last console and it has CON_CONSDEV set, we
 +	 * need to set it on the next preferred console.
 +	 */
 +	if (console_drivers != NULL && console->flags & CON_CONSDEV)
 +		console_drivers->flags |= CON_CONSDEV;
 +
 +	console_unlock();
 +	console_sysfs_notify();
 +	return res;
 +}
 +EXPORT_SYMBOL(unregister_console);
 +
 +static int __init printk_late_init(void)
 +{
 +	struct console *con;
 +
 +	for_each_console(con) {
 +		if (!keep_bootcon && con->flags & CON_BOOT) {
 +			printk(KERN_INFO "turn off boot console %s%d\n",
 +				con->name, con->index);
 +			unregister_console(con);
 +		}
 +	}
 +	hotcpu_notifier(console_cpu_notify, 0);
 +	return 0;
 +}
 +late_initcall(printk_late_init);
 +
 +#if defined CONFIG_PRINTK
 +/*
 + * Delayed printk version, for scheduler-internal messages:
 + */
 +#define PRINTK_BUF_SIZE		512
 +
 +#define PRINTK_PENDING_WAKEUP	0x01
 +#define PRINTK_PENDING_SCHED	0x02
 +
 +static DEFINE_PER_CPU(int, printk_pending);
 +static DEFINE_PER_CPU(char [PRINTK_BUF_SIZE], printk_sched_buf);
 +
 +static void wake_up_klogd_work_func(struct irq_work *irq_work)
 +{
 +	int pending = __this_cpu_xchg(printk_pending, 0);
 +
 +	if (pending & PRINTK_PENDING_SCHED) {
 +		char *buf = __get_cpu_var(printk_sched_buf);
 +		printk(KERN_WARNING "[sched_delayed] %s", buf);
 +	}
 +
 +	if (pending & PRINTK_PENDING_WAKEUP)
 +		wake_up_interruptible(&log_wait);
 +}
 +
 +static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = {
 +	.func = wake_up_klogd_work_func,
 +	.flags = IRQ_WORK_LAZY,
 +};
 +
 +void wake_up_klogd(void)
 +{
 +	preempt_disable();
 +	if (waitqueue_active(&log_wait)) {
 +		this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP);
 +		irq_work_queue(&__get_cpu_var(wake_up_klogd_work));
 +	}
 +	preempt_enable();
 +}
 +
 +int printk_sched(const char *fmt, ...)
 +{
 +	unsigned long flags;
 +	va_list args;
 +	char *buf;
 +	int r;
 +
 +	local_irq_save(flags);
 +	buf = __get_cpu_var(printk_sched_buf);
 +
 +	va_start(args, fmt);
 +	r = vsnprintf(buf, PRINTK_BUF_SIZE, fmt, args);
 +	va_end(args);
 +
 +	__this_cpu_or(printk_pending, PRINTK_PENDING_SCHED);
 +	irq_work_queue(&__get_cpu_var(wake_up_klogd_work));
 +	local_irq_restore(flags);
 +
 +	return r;
 +}
 +
 +/*
 + * printk rate limiting, lifted from the networking subsystem.
 + *
 + * This enforces a rate limit: not more than 10 kernel messages
 + * every 5s to make a denial-of-service attack impossible.
 + */
 +DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10);
 +
 +int __printk_ratelimit(const char *func)
 +{
 +	return ___ratelimit(&printk_ratelimit_state, func);
 +}
 +EXPORT_SYMBOL(__printk_ratelimit);
 +
 +/**
 + * printk_timed_ratelimit - caller-controlled printk ratelimiting
 + * @caller_jiffies: pointer to caller's state
 + * @interval_msecs: minimum interval between prints
 + *
 + * printk_timed_ratelimit() returns true if more than @interval_msecs
 + * milliseconds have elapsed since the last time printk_timed_ratelimit()
 + * returned true.
 + */
 +bool printk_timed_ratelimit(unsigned long *caller_jiffies,
 +			unsigned int interval_msecs)
 +{
 +	if (*caller_jiffies == 0
 +			|| !time_in_range(jiffies, *caller_jiffies,
 +					*caller_jiffies
 +					+ msecs_to_jiffies(interval_msecs))) {
 +		*caller_jiffies = jiffies;
 +		return true;
 +	}
 +	return false;
 +}
 +EXPORT_SYMBOL(printk_timed_ratelimit);
 +
 +static DEFINE_SPINLOCK(dump_list_lock);
 +static LIST_HEAD(dump_list);
 +
 +/**
 + * kmsg_dump_register - register a kernel log dumper.
 + * @dumper: pointer to the kmsg_dumper structure
 + *
 + * Adds a kernel log dumper to the system. The dump callback in the
 + * structure will be called when the kernel oopses or panics and must be
 + * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise.
 + */
 +int kmsg_dump_register(struct kmsg_dumper *dumper)
 +{
 +	unsigned long flags;
 +	int err = -EBUSY;
 +
 +	/* The dump callback needs to be set */
 +	if (!dumper->dump)
 +		return -EINVAL;
 +
 +	spin_lock_irqsave(&dump_list_lock, flags);
 +	/* Don't allow registering multiple times */
 +	if (!dumper->registered) {
 +		dumper->registered = 1;
 +		list_add_tail_rcu(&dumper->list, &dump_list);
 +		err = 0;
 +	}
 +	spin_unlock_irqrestore(&dump_list_lock, flags);
 +
 +	return err;
 +}
 +EXPORT_SYMBOL_GPL(kmsg_dump_register);
 +
 +/**
 + * kmsg_dump_unregister - unregister a kmsg dumper.
 + * @dumper: pointer to the kmsg_dumper structure
 + *
 + * Removes a dump device from the system. Returns zero on success and
 + * %-EINVAL otherwise.
 + */
 +int kmsg_dump_unregister(struct kmsg_dumper *dumper)
 +{
 +	unsigned long flags;
 +	int err = -EINVAL;
 +
 +	spin_lock_irqsave(&dump_list_lock, flags);
 +	if (dumper->registered) {
 +		dumper->registered = 0;
 +		list_del_rcu(&dumper->list);
 +		err = 0;
 +	}
 +	spin_unlock_irqrestore(&dump_list_lock, flags);
 +	synchronize_rcu();
 +
 +	return err;
 +}
 +EXPORT_SYMBOL_GPL(kmsg_dump_unregister);
 +
 +static bool always_kmsg_dump;
 +module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR);
 +
 +/**
 + * kmsg_dump - dump kernel log to kernel message dumpers.
 + * @reason: the reason (oops, panic etc) for dumping
 + *
 + * Call each of the registered dumper's dump() callback, which can
 + * retrieve the kmsg records with kmsg_dump_get_line() or
 + * kmsg_dump_get_buffer().
 + */
 +void kmsg_dump(enum kmsg_dump_reason reason)
 +{
 +	struct kmsg_dumper *dumper;
 +	unsigned long flags;
 +
 +	if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump)
 +		return;
 +
 +	rcu_read_lock();
 +	list_for_each_entry_rcu(dumper, &dump_list, list) {
 +		if (dumper->max_reason && reason > dumper->max_reason)
 +			continue;
 +
 +		/* initialize iterator with data about the stored records */
 +		dumper->active = true;
 +
 +		raw_spin_lock_irqsave(&logbuf_lock, flags);
 +		dumper->cur_seq = clear_seq;
 +		dumper->cur_idx = clear_idx;
 +		dumper->next_seq = log_next_seq;
 +		dumper->next_idx = log_next_idx;
 +		raw_spin_unlock_irqrestore(&logbuf_lock, flags);
 +
 +		/* invoke dumper which will iterate over records */
 +		dumper->dump(dumper, reason);
 +
 +		/* reset iterator */
 +		dumper->active = false;
 +	}
 +	rcu_read_unlock();
 +}
 +
 +/**
 + * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version)
 + * @dumper: registered kmsg dumper
 + * @syslog: include the "<4>" prefixes
 + * @line: buffer to copy the line to
 + * @size: maximum size of the buffer
 + * @len: length of line placed into buffer
 + *
 + * Start at the beginning of the kmsg buffer, with the oldest kmsg
 + * record, and copy one record into the provided buffer.
 + *
 + * Consecutive calls will return the next available record moving
 + * towards the end of the buffer with the youngest messages.
 + *
 + * A return value of FALSE indicates that there are no more records to
 + * read.
 + *
 + * The function is similar to kmsg_dump_get_line(), but grabs no locks.
 + */
 +bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
 +			       char *line, size_t size, size_t *len)
 +{
 +	struct printk_log *msg;
 +	size_t l = 0;
 +	bool ret = false;
 +
 +	if (!dumper->active)
 +		goto out;
 +
 +	if (dumper->cur_seq < log_first_seq) {
 +		/* messages are gone, move to first available one */
 +		dumper->cur_seq = log_first_seq;
 +		dumper->cur_idx = log_first_idx;
 +	}
 +
 +	/* last entry */
 +	if (dumper->cur_seq >= log_next_seq)
 +		goto out;
 +
 +	msg = log_from_idx(dumper->cur_idx);
 +	l = msg_print_text(msg, 0, syslog, line, size);
 +
 +	dumper->cur_idx = log_next(dumper->cur_idx);
 +	dumper->cur_seq++;
 +	ret = true;
 +out:
 +	if (len)
 +		*len = l;
 +	return ret;
 +}
 +
 +/**
 + * kmsg_dump_get_line - retrieve one kmsg log line
 + * @dumper: registered kmsg dumper
 + * @syslog: include the "<4>" prefixes
 + * @line: buffer to copy the line to
 + * @size: maximum size of the buffer
 + * @len: length of line placed into buffer
 + *
 + * Start at the beginning of the kmsg buffer, with the oldest kmsg
 + * record, and copy one record into the provided buffer.
 + *
 + * Consecutive calls will return the next available record moving
 + * towards the end of the buffer with the youngest messages.
 + *
 + * A return value of FALSE indicates that there are no more records to
 + * read.
 + */
 +bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
 +			char *line, size_t size, size_t *len)
 +{
 +	unsigned long flags;
 +	bool ret;
 +
 +	raw_spin_lock_irqsave(&logbuf_lock, flags);
 +	ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len);
 +	raw_spin_unlock_irqrestore(&logbuf_lock, flags);
 +
 +	return ret;
 +}
 +EXPORT_SYMBOL_GPL(kmsg_dump_get_line);
 +
 +/**
 + * kmsg_dump_get_buffer - copy kmsg log lines
 + * @dumper: registered kmsg dumper
 + * @syslog: include the "<4>" prefixes
 + * @buf: buffer to copy the line to
 + * @size: maximum size of the buffer
 + * @len: length of line placed into buffer
 + *
 + * Start at the end of the kmsg buffer and fill the provided buffer
 + * with as many of the the *youngest* kmsg records that fit into it.
 + * If the buffer is large enough, all available kmsg records will be
 + * copied with a single call.
 + *
 + * Consecutive calls will fill the buffer with the next block of
 + * available older records, not including the earlier retrieved ones.
 + *
 + * A return value of FALSE indicates that there are no more records to
 + * read.
 + */
 +bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
 +			  char *buf, size_t size, size_t *len)
 +{
 +	unsigned long flags;
 +	u64 seq;
 +	u32 idx;
 +	u64 next_seq;
 +	u32 next_idx;
 +	enum log_flags prev;
 +	size_t l = 0;
 +	bool ret = false;
 +
 +	if (!dumper->active)
 +		goto out;
 +
 +	raw_spin_lock_irqsave(&logbuf_lock, flags);
 +	if (dumper->cur_seq < log_first_seq) {
 +		/* messages are gone, move to first available one */
 +		dumper->cur_seq = log_first_seq;
 +		dumper->cur_idx = log_first_idx;
 +	}
 +
 +	/* last entry */
 +	if (dumper->cur_seq >= dumper->next_seq) {
 +		raw_spin_unlock_irqrestore(&logbuf_lock, flags);
 +		goto out;
 +	}
 +
 +	/* calculate length of entire buffer */
 +	seq = dumper->cur_seq;
 +	idx = dumper->cur_idx;
 +	prev = 0;
 +	while (seq < dumper->next_seq) {
 +		struct printk_log *msg = log_from_idx(idx);
 +
 +		l += msg_print_text(msg, prev, true, NULL, 0);
 +		idx = log_next(idx);
 +		seq++;
 +		prev = msg->flags;
 +	}
 +
 +	/* move first record forward until length fits into the buffer */
 +	seq = dumper->cur_seq;
 +	idx = dumper->cur_idx;
 +	prev = 0;
 +	while (l > size && seq < dumper->next_seq) {
 +		struct printk_log *msg = log_from_idx(idx);
 +
 +		l -= msg_print_text(msg, prev, true, NULL, 0);
 +		idx = log_next(idx);
 +		seq++;
 +		prev = msg->flags;
 +	}
 +
 +	/* last message in next interation */
 +	next_seq = seq;
 +	next_idx = idx;
 +
 +	l = 0;
 +	prev = 0;
 +	while (seq < dumper->next_seq) {
 +		struct printk_log *msg = log_from_idx(idx);
 +
 +		l += msg_print_text(msg, prev, syslog, buf + l, size - l);
 +		idx = log_next(idx);
 +		seq++;
 +		prev = msg->flags;
 +	}
 +
 +	dumper->next_seq = next_seq;
 +	dumper->next_idx = next_idx;
 +	ret = true;
 +	raw_spin_unlock_irqrestore(&logbuf_lock, flags);
 +out:
 +	if (len)
 +		*len = l;
 +	return ret;
 +}
 +EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
 +
 +/**
 + * kmsg_dump_rewind_nolock - reset the interator (unlocked version)
 + * @dumper: registered kmsg dumper
 + *
 + * Reset the dumper's iterator so that kmsg_dump_get_line() and
 + * kmsg_dump_get_buffer() can be called again and used multiple
 + * times within the same dumper.dump() callback.
 + *
 + * The function is similar to kmsg_dump_rewind(), but grabs no locks.
 + */
 +void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper)
 +{
 +	dumper->cur_seq = clear_seq;
 +	dumper->cur_idx = clear_idx;
 +	dumper->next_seq = log_next_seq;
 +	dumper->next_idx = log_next_idx;
 +}
 +
 +/**
 + * kmsg_dump_rewind - reset the interator
 + * @dumper: registered kmsg dumper
 + *
 + * Reset the dumper's iterator so that kmsg_dump_get_line() and
 + * kmsg_dump_get_buffer() can be called again and used multiple
 + * times within the same dumper.dump() callback.
 + */
 +void kmsg_dump_rewind(struct kmsg_dumper *dumper)
 +{
 +	unsigned long flags;
 +
 +	raw_spin_lock_irqsave(&logbuf_lock, flags);
 +	kmsg_dump_rewind_nolock(dumper);
 +	raw_spin_unlock_irqrestore(&logbuf_lock, flags);
 +}
 +EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
 +
 +static char dump_stack_arch_desc_str[128];
 +
 +/**
 + * dump_stack_set_arch_desc - set arch-specific str to show with task dumps
 + * @fmt: printf-style format string
 + * @...: arguments for the format string
 + *
 + * The configured string will be printed right after utsname during task
 + * dumps.  Usually used to add arch-specific system identifiers.  If an
 + * arch wants to make use of such an ID string, it should initialize this
 + * as soon as possible during boot.
 + */
 +void __init dump_stack_set_arch_desc(const char *fmt, ...)
 +{
 +	va_list args;
 +
 +	va_start(args, fmt);
 +	vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str),
 +		  fmt, args);
 +	va_end(args);
 +}
 +
 +/**
 + * dump_stack_print_info - print generic debug info for dump_stack()
 + * @log_lvl: log level
 + *
 + * Arch-specific dump_stack() implementations can use this function to
 + * print out the same debug information as the generic dump_stack().
 + */
 +void dump_stack_print_info(const char *log_lvl)
 +{
 +	printk("%sCPU: %d PID: %d Comm: %.20s %s %s %.*s\n",
 +	       log_lvl, raw_smp_processor_id(), current->pid, current->comm,
 +	       print_tainted(), init_utsname()->release,
 +	       (int)strcspn(init_utsname()->version, " "),
 +	       init_utsname()->version);
 +
 +	if (dump_stack_arch_desc_str[0] != '\0')
 +		printk("%sHardware name: %s\n",
 +		       log_lvl, dump_stack_arch_desc_str);
 +
 +	print_worker_info(log_lvl, current);
 +}
 +
 +/**
 + * show_regs_print_info - print generic debug info for show_regs()
 + * @log_lvl: log level
 + *
 + * show_regs() implementations can use this function to print out generic
 + * debug information.
 + */
 +void show_regs_print_info(const char *log_lvl)
 +{
 +	dump_stack_print_info(log_lvl);
 +
 +	printk("%stask: %p ti: %p task.ti: %p\n",
 +	       log_lvl, current, current_thread_info(),
 +	       task_thread_info(current));
 +}
 +
 +#endif